Many prior art computers have a separate interface and connector for each peripheral device. Thus the computer will have a keyboard interface and connector, a mouse interface and connector, a printer interface and connector, and so on, each of which is different and incompatible with the others. Providing a separate, additional interface for each peripheral device is expensive. While serial port connections are sometimes used, such ports typically cannot provide power to the peripheral device.
With most such prior art computers, it is impossible to simultaneously use two different pointing devices, or two keyboards, or two of any distinct type of peripheral device, because the computer has only one port and interface for each such type of peripheral device. This limitation can be inconvenient, because some users would benefit from being able to use two or more peripheral devices of the same general type. For instance, a multilingual user could use different keyboards for entering text in each of a number of different languages, or a user could use a different keyboard with each of a number of different applications, each having it's own "window" on the user's screen.
Shortcomings of certain prior art "desktop" networks, such as the "Apple Desktop Bus" on the Macintosh product line, include limitations on the length of the network caused by voltage drops along the network bus, limitations on the number of peripheral devices which may be connected to a host computer, and low data transmission speed. Further, the use of special purpose chips with some of these prior art desktop networks prevents other manufacturers from making peripheral devices that work with the desktop network.
Another shortcoming of the prior art is the inability to work with "hybrid" peripheral devices that contain two or more sub-devices, such as a keyboard with a built-in track ball and/or LED display. Other shortcomings of the prior art which are overcome by the present invention include the need for the host computer to poll all peripheral devices, which imposes a computational burden on the host computer, and the inability of the prior art devices to handle "hot plugging" of peripheral devices onto the network without having to reset the entire network.